How do i get my girlfriend to stop wanting her ex and get her ex to stay out of our relationship?

i have a small problem. me and my girlfriend have been dating since july 25 till now. she has a ex who she carried his kid for 4 months and then had a miscarriage and lost the baby. she has a inner connection with this ex for that reason. well she tells me she is totally devoted to me but she is now in fayette, mo. which is approx. 2 hours away from me. i work 6 to 7 days a week and crazy hours so i never really get to see her. she has been in fayette for a month going to college and gradually over time im starting to find out more and more about her that is very disturbing things that i dont know if i can handle them or not. i realized that she had a connection with her ex but it was a bit out of control. i was told that before they were together they were best friends. also, when i used to travel the hour an a half to go see her every weekend i noticed that he was always calling or texing her. she would never take his phone calls when i was around even when i told her to answer it and he interupts a large percentage of our alone time , taking her focus off me with his texts that she just "had" to answer. i informed her of my supreme dislike for him and that he was just her ex now and that he shouldn't be a higher priority then me to her. she agreed to stop talking to him. told me she was erasing anything she had the would let her have contact with him. i belived her. and up to this point after she left for school she never made time for me until i told her to stop putting me second to everything. a week pes and she talked to me all the time and i was happy again but now i found out that she hides anything she is doing with him from me and she recently behind my back had him drive her the 2 hours back home from her school knowing that would highly upset me. this isn't the first time she has lied to me. and really i cant say lied cause its more along the lines of hiding the important parts of stories. my last relationship ended because of my ex doing what this girl is doing to me only i am not letting it walk this time. what should i do? i dont know if i can trust her anymore. but i love her. the bigger problem is that her ex wont back off either. i honestly cant say im perfect by any means but this man has mental issues. he tells me that they had a "Good time " when he was with her on that 2 hour trip but she says all he did was take her home and that he is just trying to upset me. this could just be another cover up of hers so i dont know what to believe anymore. can somebody help advise me?